Here the sow is not mated at the first oestrus post-weaning but at the second. This is a procedure worth considering if the second litter size is poor. Often the first parity weaning to first service interval is extended which could be the cause of the smaller second litter. However a second litter size drop may occur even if the weaning to service interval is normal (less than 7 days).

There are no economic advantages in skipping services in sows after 2 litters.

Young sows are more prone to convert both fat and protein into energy and if this process of metabolism is a negative or catabolic one, (i.e. more energy is leaving the sow than is entering via feed) the hormone control of reproduction is affected. Skipped sows will be depositing protein and fat and are therefore anabolic at the time of mating with improved reproductive efficiency.

Is it worth skip mating?

• Probably if there is a second litter size problem that cannot be solved by feed intake in lactation.
• If the increase in litter size is 2.1 pigs weaned then the 21 non-productive days lost and its consequences would be out weighed by an increase in 0.8 pigs per sow per annum.
• Practical problems such as housing and movement of the second litter female can sometimes create difficulties.
• Try the technique on a few sows first and see if it is worth while.